diff --git a/backup/backup.go b/backup/backup.go
index df3fb047b..bb497a5cd 100644
--- a/backup/backup.go
+++ b/backup/backup.go
@@ -249,8 +249,15 @@ func (bm *BackupManager) ChoosePod(ctx context.Context, pods []*corev1.Pod) (int
 		}
 	}
 
-	lastIndex := lastBackup.SourceIndex
-	choosableIndexes := getIdxsWithUnchangedUUID(bm.uuidSet, lastBackup.UUIDSet)
+	var choosableIndexes []int
+	// for backward compatibility
+	// if lastBackup.UUIDSet is empty, use lastBackup.SourceUUID
+	if len(lastBackup.UUIDSet) == 0 {
+		s := map[string]string{strconv.Itoa(lastBackup.SourceIndex): lastBackup.SourceUUID}
+		choosableIndexes = getIdxsWithUnchangedUUID(bm.uuidSet, s)
+	} else {
+		choosableIndexes = getIdxsWithUnchangedUUID(bm.uuidSet, lastBackup.UUIDSet)
+	}
 
 	if len(choosableIndexes) == 0 {
 		bm.log.Info("the server_uuid of all pods has changed or some pods are not ready")
@@ -271,6 +278,7 @@ func (bm *BackupManager) ChoosePod(ctx context.Context, pods []*corev1.Pod) (int
 	}
 
 	replicas := []int{}
+	lastIndex := lastBackup.SourceIndex
 	for _, i := range choosableIndexes {
 		if i == currentPrimaryIndex {
 			continue
diff --git a/backup/backup_test.go b/backup/backup_test.go
index 5dff432d0..b85b29fb5 100644
--- a/backup/backup_test.go
+++ b/backup/backup_test.go
@@ -168,6 +168,12 @@ func TestGetIdxsWithUnchangedUUID(t *testing.T) {
 
 		expectIdxs []int
 	}{
+		{
+			name:       "last-empty",
+			current:    map[string]string{"0": "uuid-0"},
+			last:       map[string]string{},
+			expectIdxs: []int{},
+		},
 		{
 			name:       "single-uuid-not-changed",
 			current:    map[string]string{"0": "uuid-0"},
@@ -250,11 +256,11 @@ func TestChoosePod(t *testing.T) {
 		}
 	}
 
-	makeBS := func(sourceIdx int, uuidSet map[string]string) mocov1beta2.BackupStatus {
+	makeBS := func(sourceIdx int, sourceUUID string, uuidSet map[string]string) mocov1beta2.BackupStatus {
 		return mocov1beta2.BackupStatus{
 			Time:        metav1.Now(),
 			SourceIndex: sourceIdx,
-			SourceUUID:  uuidSet[strconv.Itoa(sourceIdx)],
+			SourceUUID:  sourceUUID,
 			UUIDSet:     uuidSet,
 		}
 	}
@@ -326,11 +332,33 @@ func TestChoosePod(t *testing.T) {
 			doBackupBinlog: false,
 			warnings:       0,
 		},
+		{
+			name:           "triple-last-uuid-set-is-empty",
+			replicas:       3,
+			current:        1,
+			bkup:           makeBS(2, "uuid-2", map[string]string{}),
+			pods:           makePod3(true, true, true),
+			err:            nil,
+			expectIdx:      2,
+			doBackupBinlog: true,
+			warnings:       0,
+		},
+		{
+			name:           "triple-last-uuid-set-is-empty-source-uuid-changed",
+			replicas:       3,
+			current:        1,
+			bkup:           makeBS(2, "uuid-b", map[string]string{}),
+			pods:           makePod3(true, true, true),
+			err:            nil,
+			expectIdx:      0,
+			doBackupBinlog: false,
+			warnings:       1,
+		},
 		{
 			name:           "single-2nd",
 			replicas:       1,
 			current:        0,
-			bkup:           makeBS(0, map[string]string{"0": "uuid-0"}),
+			bkup:           makeBS(0, "uuid-0", map[string]string{"0": "uuid-0"}),
 			pods:           makePod1(true),
 			err:            nil,
 			expectIdx:      0,
@@ -341,7 +369,7 @@ func TestChoosePod(t *testing.T) {
 			name:           "single-2nd-uuid-changed",
 			replicas:       1,
 			current:        0,
-			bkup:           makeBS(0, map[string]string{"0": "uuid-a"}),
+			bkup:           makeBS(0, "uuid-a", map[string]string{"0": "uuid-a"}),
 			pods:           makePod1(true),
 			err:            nil,
 			expectIdx:      0,
@@ -352,7 +380,7 @@ func TestChoosePod(t *testing.T) {
 			name:           "single-2nd-not-ready",
 			replicas:       1,
 			current:        0,
-			bkup:           makeBS(0, map[string]string{"0": "uuid-0"}),
+			bkup:           makeBS(0, "uuid-0", map[string]string{"0": "uuid-0"}),
 			pods:           makePod1(false),
 			err:            errors.New("no ready pod exists"),
 			expectIdx:      0,
@@ -363,7 +391,7 @@ func TestChoosePod(t *testing.T) {
 			name:           "triple-2nd",
 			replicas:       3,
 			current:        0,
-			bkup:           makeBS(1, map[string]string{"0": "uuid-0", "1": "uuid-1", "2": "uuid-2"}),
+			bkup:           makeBS(1, "uuid-1", map[string]string{"0": "uuid-0", "1": "uuid-1", "2": "uuid-2"}),
 			pods:           makePod3(true, true, true),
 			err:            nil,
 			expectIdx:      1,
@@ -374,7 +402,7 @@ func TestChoosePod(t *testing.T) {
 			name:           "triple-2nd-uuid-changed",
 			replicas:       3,
 			current:        0,
-			bkup:           makeBS(1, map[string]string{"0": "uuid-0", "1": "uuid-b", "2": "uuid-2"}),
+			bkup:           makeBS(1, "uuid-b", map[string]string{"0": "uuid-0", "1": "uuid-b", "2": "uuid-2"}),
 			pods:           makePod3(true, true, true),
 			err:            nil,
 			expectIdx:      2,
@@ -385,7 +413,7 @@ func TestChoosePod(t *testing.T) {
 			name:           "triple-2nd-last-index-not-ready",
 			replicas:       3,
 			current:        0,
-			bkup:           makeBS(1, map[string]string{"0": "uuid-0", "1": "uuid-1", "2": "uuid-2"}),
+			bkup:           makeBS(1, "uuid-1", map[string]string{"0": "uuid-0", "1": "uuid-1", "2": "uuid-2"}),
 			pods:           makePod3(true, false, true),
 			err:            nil,
 			expectIdx:      2,
@@ -396,7 +424,7 @@ func TestChoosePod(t *testing.T) {
 			name:           "triple-2nd-primary",
 			replicas:       3,
 			current:        1,
-			bkup:           makeBS(1, map[string]string{"0": "uuid-0", "1": "uuid-1", "2": "uuid-2"}),
+			bkup:           makeBS(1, "uuid-1", map[string]string{"0": "uuid-0", "1": "uuid-1", "2": "uuid-2"}),
 			pods:           makePod3(true, true, true),
 			err:            nil,
 			expectIdx:      0,
@@ -407,7 +435,7 @@ func TestChoosePod(t *testing.T) {
 			name:           "triple-2nd-all-not-ready",
 			replicas:       3,
 			current:        0,
-			bkup:           makeBS(1, map[string]string{"0": "uuid-0", "1": "uuid-1", "2": "uuid-2"}),
+			bkup:           makeBS(1, "uuid-1", map[string]string{"0": "uuid-0", "1": "uuid-1", "2": "uuid-2"}),
 			pods:           makePod3(false, false, false),
 			err:            errors.New("no ready pod exists"),
 			expectIdx:      0,
@@ -418,7 +446,7 @@ func TestChoosePod(t *testing.T) {
 			name:           "triple-2nd-replica-uuid-changed",
 			replicas:       3,
 			current:        0,
-			bkup:           makeBS(1, map[string]string{"0": "uuid-0", "1": "uuid-a", "2": "uuid-b"}),
+			bkup:           makeBS(1, "uuid-a", map[string]string{"0": "uuid-0", "1": "uuid-a", "2": "uuid-b"}),
 			pods:           makePod3(true, true, true),
 			err:            nil,
 			expectIdx:      0,
@@ -429,7 +457,7 @@ func TestChoosePod(t *testing.T) {
 			name:           "triple-2nd-some-not-ready-and-uuid-changed-1",
 			replicas:       3,
 			current:        0,
-			bkup:           makeBS(1, map[string]string{"0": "uuid-a", "1": "uuid-1", "2": "uuid-b"}),
+			bkup:           makeBS(1, "uuid-1", map[string]string{"0": "uuid-a", "1": "uuid-1", "2": "uuid-b"}),
 			pods:           makePod3(true, false, true),
 			err:            nil,
 			expectIdx:      2,
@@ -440,7 +468,7 @@ func TestChoosePod(t *testing.T) {
 			name:           "triple-2nd-some-not-ready-and-uuid-changed-2",
 			replicas:       3,
 			current:        0,
-			bkup:           makeBS(0, map[string]string{"0": "uuid-a", "1": "uuid-1", "2": "uuid-b"}),
+			bkup:           makeBS(0, "uuid-a", map[string]string{"0": "uuid-a", "1": "uuid-1", "2": "uuid-b"}),
 			pods:           makePod3(true, false, false),
 			err:            nil,
 			expectIdx:      0,